The present invention relates to an automatic air bleed-off valve, and more particularly to an air bleed-off valve suitable for use with a spa.
Spas include a pump and heater to provide a flow of heated water to jets as shown in prior art FIG. 1. The pump sucks water through drains and pumps the water through the heater to jets mounted in spa walls. If sufficient air enters the pump, and is pumped through the heater, overheating and damage to the heater may result. Many modern spas include at least two drains as a safety requirement to prevent a user from being held against a drain by pump suction. Because of the additional drains, there is a greater likelihood that one drain will allow air to enter the system and reach the heater. There is thus a need for a valve to automatically bleed off air before the air can reach and damage the heater.
U.S. Pat. No. 3,197,069 issued Jul. 27, 1965 for “System for Dispensing Liquid Having a Meter, an Air Eliminator, and a Back Pressure Valve,” describes an air eliminator used with a back pressure valve for use with a fuel delivery truck. The air eliminator of the '069 patent includes a float attached to a valve. Unfortunately, the float and valve arrangement requires at least twenty five pounds of back pressure to properly function, and creating artificial back pressure in a spa would reduce the effect of the jets.
U.S. Pat. No. 5,263,459 issued Nov. 23, 1993 for “Fuel Delivery with Self-Priming Fuel Pump,” describes an air/vapor purge valve for purging air and/or vapor from a fuel line. The air/vapor purge valve of the '459 patent is downward pointing, and is spring loaded in an open position.
U.S. Pat. No. 6,003,167 issued Dec. 21, 1999 for “Apparatus for Eliminating Gas from a Fluid Piping System,” describes a system for removing gas from a recirculating spa or hydrotherapy tub to prevent gas from being trapped in a pump housing. The gas is removed by routing pipe to a vent above the pump, however, the '167 patent does not describe a valve or cooperation of a valve with a heater and does not suggest that the vent will remove air from a pump and heater combination in a spa.